III. The preparation of medicines from the crude drug is carried on in drug mills and pharmacies by many processes of great nicety and by exact formulae which place them, when completed, in distinct classes, each class differing from all others in one or more particulars. To standardize the preparation of drugs, each country has its Pharmacopoeia, or authorized publication containing the list of such drugs and their preparations as are declared official for that country. Abroad the national Pharmacopoeias are established by law. In this country, representatives of the medical and pharmaceutical professions together formulate the U. S. P., and appoint a committee to revise it every ten years.

Dispensatories are private unofficial publications -commentaries on the Pharmacopoeia, treating with much detail not only those official drugs contained in it, but unofficial ones, and their preparations also. The Dispensatory and the Pharmacopoeia both give doses. The classes of preparations of the U. S. P. are as follows, a few being omitted as unimportant:

Liquid Preparations

Emulsions, Emulsa. Elixirs, Elixiria. Infusions, Infusa. Solutions, Liquores. Waters, Aquoe. Tinctures, Tincturoe, Fluidextracts, Fluidextracta. Spirits, Spiritus. Mixtures, Misturoe. Vinegars, Aceta. Oleates, Oleata. Oleoresins, Oleoresinoe. Glycerites, Glycerita. Syrups, Syrupi. Mucilages, Mucilagines. Liniments, Linimenta.

Solid Preparations

Extracts, Extracta. Resins, Resinoe. Cerates, Cerata. Pills, Piluloe. Powders, Pulveres. Papers, Charta. Ointments, Unguenta. Plasters, Emplastra. Suppositories, Suppositoria. Troches, Trochisci.